CN111868194A - Adhesive, adhesive tape, and method for securing electronic equipment part or vehicle-mounted part - Google Patents

Abstract

The purpose of the present invention is to provide an adhesive that can improve the content of biogenic carbon and at the same time exhibit excellent adhesive strength, an adhesive tape using the adhesive, and a method for fixing electronic device components or vehicle-mounted components. The present invention is an adhesive comprising a (meth) acrylic copolymer containing 48 wt% or more of a structural unit derived from a monomer A and/or a monomer B, wherein the monomer A contains biogenic carbon and is represented by general formula (1), and the monomer B contains biogenic carbon and is represented by general formula (2), and the glass transition temperature of the (meth) acrylic copolymer is-20 ℃ or lower.

Description

Adhesive, adhesive tape, and method for securing electronic equipment part or vehicle-mounted part

technical field

The present invention relates to adhesives, adhesive tapes, and methods of securing electronic equipment components or vehicle components.

Background technique

Conventionally, in electronic parts, vehicles, houses, and building materials, when fixing parts, adhesive tapes having an adhesive layer containing an adhesive have been widely used. Specifically, for example, in order to bond a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to bond a touch panel module to a display panel module, an adhesive sheet (eg patented References 1 to 3).

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2015-052050

Patent Document 2: Japanese Patent Laid-Open No. 2015-021067

Patent Document 3: Japanese Patent Laid-Open No. 2015-120876

SUMMARY OF THE INVENTION

The problem to be solved by the invention

In recent years, exhaustion of petroleum resources and emission of carbon dioxide due to combustion of petroleum-derived products have been regarded as problems. Therefore, mainly in the medical field and the packaging material field, an attempt has been made to save petroleum resources by using bio-derived materials instead of petroleum-derived materials. Such attempts are gradually spreading to all fields, and even in the fields of adhesives and adhesive tapes, the use of biologically derived materials is required.

As an adhesive excellent in adhesive force, (meth)acrylic adhesive containing a (meth)acrylic copolymer is widely used. Even if it is a (meth)acrylic-type adhesive, a bio-derived material can be selected and used, for example, a rosin, a terpene, etc. can be used as a tackifier, etc. However, it is difficult to exert an excellent adhesive force while making a large amount of material biologically derived.

An object of the present invention is to provide an adhesive capable of exhibiting excellent adhesive force while increasing the content of bio-derived carbon, an adhesive tape using the adhesive, and fixing electronic equipment parts or vehicles component method.

means of solving problems

The present invention is an adhesive comprising a (meth)acrylic copolymer containing more than 48% by weight of structural units derived from monomer A and/or monomer B, and the glass transition temperature of the (meth)acrylic copolymer is −20° C. or lower, wherein the monomer A contains bioderived carbon and is represented by the following general formula (1), the monomer B contains biologically derived carbon and is represented by the following general formula (2).

[Chemical formula 1]

In formula (1), R ¹ represents H or CH ₃ , R ² represents -C _n H _2n+1 , and n represents an integer of 7-14.

In formula (2), R ³ represents -C(=O)C _m H _2m+1 , and m represents an integer of 7-13.

The carbon in R ² and R ³ is biologically derived carbon.

Hereinafter, the present invention will be described in detail.

The inventors of the present application have conducted intensive research, and as a result found that, by selecting a monomer A (hereinafter, also simply referred to as "monomer A") represented by the above-mentioned general formula (1) containing bioderived carbon and/or Monomer B (hereinafter, also simply referred to as "monomer B") which contains carbon of biological origin and is represented by the above-mentioned general formula (2) is used as a raw material of the (meth)acrylic copolymer constituting the binder, and By setting the glass transition temperature of the (meth)acrylic copolymer to be -20°C or lower, an adhesive capable of exhibiting an excellent adhesive force while increasing the content of bioderived carbon can be obtained.

The adhesive which is one Embodiment of this invention contains a (meth)acrylic-type copolymer. Such a (meth)acrylic pressure-sensitive adhesive can exhibit excellent adhesive force by selecting a monomer as a raw material.

In this invention, the said monomer A and/or the said monomer B are contained in the monomer which is a raw material of a (meth)acrylic-type adhesive.

These monomers can be obtained inexpensively and easily by alcoholizing and esterifying saturated fatty acids and unsaturated fatty acids extracted from animals and plants as raw materials. If the monomers A and B containing plant-derived carbon are used, they are originally resources generated by taking carbon dioxide in the atmosphere. Therefore, even if they are burned, the total amount of carbon dioxide in the atmosphere will not increase. . Homopolymers of these monomers have a low glass transition temperature, and are more likely to exhibit the adhesive function of the adhesive formed from the monomers. Therefore, they can be used in a large amount to improve the biogenic property of the adhesive as a whole. The content of carbon can be combined with other non-biological monomers arbitrarily to produce an adhesive that exhibits sufficient adhesive force.

The alkyl group contained in R ² in the formula (1) and R ³ in the formula (2) may be linear or branched. Since the cohesion force is high and a higher adhesive force can be obtained, a linear form is preferable.

Specific examples of the monomer A include n-octyl (meth)acrylate, lauryl (meth)acrylate, n-decyl (meth)acrylate, n-heptyl acrylate, and (meth)acrylic acid. 2-octyl ester, n-nonyl (meth)acrylate, undecyl (meth)acrylate, tetradecyl (meth)acrylate, myristyl (meth)acrylate, and the like. These monomers A may be used alone or in combination of two or more. Among them, those selected from the group consisting of normal (meth)acrylic acid are preferable because they are particularly easy to obtain, the glass transition temperature of the homopolymer is also low, and the adhesive function of the adhesive composed of the monomer is easily exhibited. At least one of octyl ester, lauryl (meth)acrylate, and decyl (meth)acrylate. Among them, from the viewpoint of obtaining an adhesive excellent in shear force, the monomer A more preferably contains lauryl acrylate and/or lauryl methacrylate, and further preferably contains lauryl acrylate and lauryl methacrylate.

As said monomer B, specifically, vinyl caprate, vinyl laurate, vinyl octanoate, vinyl nonanoate, etc. are mentioned, for example. These monomers B may be used alone or in combination of two or more. Among them, vinyl caprate and/or lauric acid are preferable because they are particularly easy to obtain, the glass transition temperature of the homopolymer is also low, and the adhesive function of the adhesive composed of the monomer is easily exhibited. vinyl acetate.

The above-mentioned (meth)acrylic copolymer contains 48% by weight or more of structural units derived from the above-mentioned monomer A and/or monomer B. Thereby, it is possible to exhibit an excellent adhesive force while increasing the content of bio-derived carbon. From the viewpoint of further improving the adhesive force, the (meth)acrylic copolymer preferably contains 55% by weight or more of structural units derived from the above-mentioned monomer A and/or monomer B, and further preferably contains 65% by weight or more, It is particularly preferable to contain 75% by weight or more, and usually 100% by weight or less.

When the above-mentioned (meth)acrylic copolymer contains the above-mentioned structural unit derived from the monomer A, among the above-mentioned structural units derived from the monomer A, from the viewpoint of further improving the adhesive force, lauryl acrylate and /or the structural unit of lauryl methacrylate is 48% by weight or more.

The content of the structural unit derived from lauryl acrylate in the total of the structural units derived from lauryl acrylate and/or lauryl methacrylate is preferably 10% by weight or more and 90% by weight or less, more preferably 15% by weight Not less than 85% by weight and not more than 85% by weight, more preferably not less than 19% by weight and not more than 77% by weight.

In addition, the content of the structural unit derived from lauryl methacrylate in the total of the structural units derived from lauryl acrylate and/or lauryl methacrylate is preferably 10% by weight or more and 90% by weight or less, more preferably It is 15 weight% or more and 85 weight% or less, More preferably, it is 19 weight% or more and 77 weight% or less.

The above-mentioned (meth)acrylic copolymer may contain structural units derived from other monomers than the above-mentioned monomer A and monomer B.

It does not specifically limit as said other monomer, For example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, (meth)acrylate ) tert-butyl acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, (meth)acrylic acid Isononyl ester, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, 5,7,7-trimethyl-2-(1,3,3- Esters of trimethylbutyl) octanol-1 and (meth)acrylic acid, alcohols having 1 or 2 methyl groups in the linear main chain and having a total carbon number of 18 and (meth)acrylic acid (meth)acrylic acid alkyl esters such as behenyl (meth)acrylate, arachidyl (meth)acrylate, etc.

In addition, for example, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, and (meth)acrylic acid are mentioned. 2-phenoxyethyl ester, tetrahydrofurfuryl (meth)acrylate, polypropylene glycol mono(meth)acrylate, etc.

Further, for example, (meth)acrylates having a hydroxyl group such as 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate can be used. For example, a monomer having a carboxyl group such as (meth)acrylic acid can be used. For example, a monomer having a glycidyl group such as glycidyl (meth)acrylate can be used. For example, a monomer having an amide group such as hydroxyethyl (meth)acrylamide, isopropyl (meth)acrylamide, and dimethylaminopropyl (meth)acrylamide can be used. A monomer having a nitrile group such as (meth)acrylonitrile can be used.

Furthermore, for example, various monomers generally used in (meth)acrylic polymers such as vinyl carboxylates such as vinyl acetate, acrylonitrile, and styrene can also be used.

These monomers may be used alone or in combination of two or more.

Among them, the (meth)acrylic copolymer preferably has, as the other monomers described above, from the viewpoint of improving the adhesiveness to resins such as polypropylene and acrylic resins such as olefin resins. The structural unit of the alkyl (meth)acrylate which has a C16-24 (preferably 18-23, more preferably 20-22) alkyl group.

The other monomers described above are preferably monomers containing biologically derived carbon, but may be non-biologically derived monomers that do not contain biologically derived carbon. Theoretically, it is also possible to make all the monomers used as raw materials of the acrylic copolymer be monomers containing bioderived carbon. From the viewpoints of the cost and productivity of the binder, a relatively inexpensive and easily available monomer containing carbon derived from biomass can be used, or it can be combined with a monomer containing carbon derived from petroleum.

The glass transition temperature of the above-mentioned (meth)acrylic copolymer is -20°C or lower. Thereby, the obtained adhesive can exhibit excellent adhesive force. From the viewpoint of further improving the adhesive force, the glass transition temperature of the (meth)acrylic copolymer is preferably -30°C or lower, more preferably -40°C or lower, and particularly preferably -50°C or lower. The glass transition temperature of the said (meth)acrylic-type copolymer is -90 degreeC or more normally, Preferably it is -80 degreeC or more.

The glass transition temperature of the said (meth)acrylic-type copolymer can be calculated|required by differential scanning calorimetry, for example.

The weight average molecular weight of the (meth)acrylic copolymer is not particularly limited, but the preferred lower limit is 300,000, and the preferred upper limit is 2,000,000. When the weight average molecular weight of the said (meth)acrylic-type copolymer is this range, the adhesive force obtained can show the outstanding adhesive force. A more preferable lower limit of the weight average molecular weight of the (meth)acrylic copolymer is 400,000, a more preferable upper limit is 1,800,000, a further preferable lower limit is 500,000, and a particularly preferable lower limit is 1,000,000.

In addition, in this specification, the weight average molecular weight means the polystyrene conversion molecular weight calculated|required by GPC measurement.

The said (meth)acrylic-type copolymer can be obtained by radically reacting the mixture of the monomer which is the said raw material in presence of a polymerization initiator.

The form of the radical reaction is not particularly limited, and examples thereof include living radical polymerization, free radical polymerization, and the like. According to living radical polymerization, a copolymer having a more uniform molecular weight and composition than free radical polymerization can be obtained, the production of low molecular weight components and the like is suppressed, and the cohesive force of the pressure-sensitive adhesive layer becomes high.

The polymerization method is not particularly limited, and conventionally known methods can be used. For example, solution polymerization (boiling point polymerization or isothermal polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, etc. are mentioned. Among them, solution polymerization is preferable from the viewpoint of easiness of synthesis.

When using solution polymerization as a polymerization method, as a reaction solvent, ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, diethyl ether, etc. are mentioned, for example. These reaction solvents may be used alone or in combination.

The said polymerization initiator is not specifically limited, For example, an organic peroxide, an azo compound, etc. are mentioned. As said organic peroxide, 1,1-bis(tert-hexylperoxide)-3,3,5-trimethylcyclohexane, tert-hexyl peroxypivalate, peroxypivalic acid are mentioned, for example tert-Butyl ester, 2,5-dimethyl-2,5-bis(2-ethylhexanoic acid peroxy)hexane, tert-hexyl peroxy-2-ethylhexanoate, peroxy-2-ethyl Tert-butyl caproate, tert-butyl peroxyisobutyrate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, etc. As said azo compound, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, etc. are mentioned, for example. These polymerization initiators may be used alone or in combination of two or more.

Moreover, in the case of living radical polymerization, as said polymerization initiator, an organic tellurium polymerization initiator is mentioned, for example. The above-mentioned organic tellurium polymerization initiator is not particularly limited as long as it is a polymerization initiator generally used in living radical polymerization, and examples thereof include organic tellurium compounds, organic tellurium compounds, and the like. In addition, in the living radical polymerization, in addition to the above-mentioned organic tellurium polymerization initiator, an azo compound may be further used as the above-mentioned polymerization initiator for the purpose of accelerating the polymerization rate.

From the viewpoint of appropriately adjusting the gel percentage, it is preferable that the pressure-sensitive adhesive as one embodiment of the present invention further contains a crosslinking agent.

The said crosslinking agent is not specifically limited, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned.

It is preferable that the adhesive which is one Embodiment of this invention further contains a tackifier from the viewpoint of being able to improve the adhesiveness to an adherend.

Examples of the tackifier include rosin-based tackifiers such as rosin-based resins, rosin ester-based resins, and hydrogenated rosin-based resins; terpene-based tackifiers such as terpene-based resins and terpene-phenol-based resins; Ketone indene resins, alicyclic saturated hydrocarbon resins, C5-based petroleum resins, C9-based petroleum resins, C5-C9 copolymerized petroleum resins, etc. These tackifier resins may be used alone or in combination of two or more. Among them, bio-derived rosin-based thickeners and terpene-based thickeners are suitable. Examples of the bio-derived tackifier include rosin-based resins derived from natural resins such as rosin, and terpene-based resins such as plant-derived essential oils.

When the said pressure-sensitive adhesive layer contains the said tackifier, the content of the said tackifier is not particularly limited, but the preferred lower limit is 10 parts by weight with respect to 100 parts by weight of the (meth)acrylic copolymer, A preferable upper limit is 50 parts by weight. When content of the said tackifier is this range, the adhesive force obtained can exhibit sufficient adhesive force.

The adhesive which is one Embodiment of this invention can contain additives, such as a silane coupling agent, a plasticizer, an emulsifier, a softener, a filler, a pigment, a dye, etc. as needed. As these additives, materials of biological origin are also preferably selected to the extent possible.

It is preferable that the content rate of bio-derived carbon which is the binder of one Embodiment of this invention is 40 weight% or more. The content rate of bio-derived carbon of 40% by weight or more becomes the standard for "bio-based products". From the viewpoint of reducing the load on the environment as a pressure-sensitive adhesive tape, the content of bio-derived carbon as the pressure-sensitive adhesive of one embodiment of the present invention is more preferably 60% by weight or more, usually 100% by weight the following.

Bio-derived carbon contains a certain proportion of radioactive isotopes (C-14), whereas petroleum-derived carbon contains almost no C-14. Therefore, the content rate of the above-mentioned biologically derived carbon can be calculated by measuring the concentration of C-14 contained in the adhesive tape. Specifically, it can be measured according to ASTM D6866, which is a standard used in many bioplastic industries.

Moreover, the adhesive tape which has the adhesive layer containing the said adhesive is also one of this invention.

The pressure-sensitive adhesive tape as one embodiment of the present invention may be an unsupported pressure-sensitive adhesive tape without a base material, a single-sided pressure-sensitive adhesive tape having an pressure-sensitive adhesive layer on one surface of a base material, or a base material-based pressure-sensitive adhesive tape. Double-sided adhesive tape with adhesive layers on both sides of the material.

Although it does not specifically limit as said base material, A conventionally well-known base material can be used, However, in order to increase the content rate of bio-derived carbon as a whole adhesive tape, it is preferable to use a bio-derived base material.

As the above-mentioned biologically derived base material, for example, polyethylene terephthalate (PET), polyethylene furandicarboxylate (PEF), polylactic acid (PLA), polyethylene terephthalate (polyparaphenylene) derived from plants can be mentioned. Polyester (PES) such as trimethylene dicarboxylate (PTT), polybutylene terephthalate (PBT), polybutylene succinate (PBS), polyethylene (PE), polypropylene (PP), Films formed of polyurethane (PU), triacetyl cellulose (TAC), cellulose, polyamide (PA), etc., as well as nonwoven fabrics, etc.

From the viewpoint of the strength of the base material, the base material is preferably a film formed of PES or a film formed of PA. Furthermore, from the viewpoint of heat resistance and oil resistance, a film formed of PA is preferable.

Examples of the constituents of the film made of PA include nylon 11, nylon 1010, nylon 610, nylon 510, nylon 410, etc. using castor oil as a raw material; nylon 56, etc., using cellulose as a raw material.

In addition, from the viewpoint of reducing the amount of carbon dioxide emissions by reducing the amount of new petroleum resources used and reducing the amount of carbon dioxide emissions, it is possible to use a base material that utilizes renewable resources. As a method of recycling resources, for example, wastes such as packaging containers, household appliances, automobiles, building materials, and foodstuffs are recovered, and wastes generated in manufacturing processes are collected, and the extracted materials are washed, decontaminated, or heated or fermented. The method of decomposition and reuse as raw material. Examples of substrates using recycled resources include films made of PET, PBT, PE, PP, PA, etc., and nonwoven fabrics, which are obtained by re-resinizing recovered plastics as raw materials. Wait. In addition, the recovered waste can be burned to be used as heat energy related to the production of the base material and its raw material, and the oil and fat contained in the recovered waste can be mixed with petroleum, fractionated, and purified. used as raw material.

In another embodiment of the present invention, the substrate may be a foam substrate from the viewpoint of improving the compression properties.

As the above-mentioned foam base material, a foam base material composed of PE, PP and/or PU is preferable, and a foam body base material composed of PE is more preferable from the viewpoint of high compatibility of flexibility and strength. . As a structure of the foam base material which consists of PE, PE etc. which use sugarcane as a raw material are mentioned, for example.

The manufacturing method of the said foam base material is not specifically limited, For example, the following method is preferable: prepare a foamable resin composition containing PE resin containing PE using sugarcane as a raw material, and a foaming agent, and use an extruder to extrude the foamed resin composition. A method of extruding the foamable resin composition into a sheet shape, foaming a foaming agent at this time, and crosslinking the obtained polyolefin foam as necessary.

The thickness of the said foam base material is not specifically limited, A preferable lower limit is 50 micrometers, and a preferable upper limit is 300 micrometers. When the thickness of the said foam base material exists in this range, high impact resistance can be exhibited, and high flexibility which can be adhered closely along the shape of an adherend can be exhibited.

The lower limit of the gel fraction of the pressure-sensitive adhesive layer is preferably 10% by weight, the lower limit is more preferably 20% by weight, the upper limit is preferably 70% by weight, and the upper limit is more preferably 50% by weight. When the said gel percentage is in this range, the adhesive tape obtained can exhibit sufficient adhesive force.

In addition, the gel percentage was measured as follows. First, the adhesive tape was cut into a flat rectangle of 50 mm × 100 mm to produce a test piece. After immersing the test piece in ethyl acetate at 23°C for 24 hours, it was taken out from the ethyl acetate and kept at 110°C. Let it dry for 1 hour. The weight of the test piece after drying was measured, and the gel percentage was calculated using the following formula. In addition, the release film for protecting the pressure-sensitive adhesive layer was not laminated|stacked on the test piece.

Gel percentage (wt%)=100×(W2-W0)/(W1-W0)

(W0: weight of base material, W1: weight of test piece before immersion, W2: weight of test piece after immersion and drying)

The thickness of the said adhesive layer is not specifically limited, A preferable lower limit is 10 micrometers, and a preferable upper limit is 100 micrometers. When the thickness of the said adhesive layer is this range, the adhesive tape obtained can exhibit sufficient adhesive force.

In the pressure-sensitive adhesive tape according to one embodiment of the present invention, the preferred lower limit of the total thickness of the pressure-sensitive adhesive tape (the total thickness of the base material and the pressure-sensitive adhesive layer) is 10 μm, and the preferred upper limit is 400 μm. When the total thickness of the pressure-sensitive adhesive tape is within this range, the obtained pressure-sensitive adhesive tape can exhibit sufficient adhesive force.

The manufacturing method of the adhesive tape which is one Embodiment of this invention is not specifically limited, It can manufacture by the conventionally well-known manufacturing method. For example, in the case of a double-sided pressure-sensitive adhesive tape, the following methods are exemplified.

First, a solvent is added to the (meth)acrylic copolymer and, if necessary, a crosslinking agent, a tackifier, and the like to prepare a solution of the adhesive A, and the solution of the adhesive A is applied on On the surface of the base material, the solvent in the solution was completely removed by drying, whereby the pressure-sensitive adhesive layer A was formed. Next, on the pressure-sensitive adhesive layer A formed, the release film was superimposed on the pressure-sensitive adhesive layer A with its release-treated surface.

Next, another release film other than the above-mentioned release film was prepared, the solution of the adhesive B was applied to the release treatment surface of the release film, and the solvent in the solution was completely dried and removed, thereby producing a The laminated film of the pressure-sensitive adhesive layer B is formed on the surface of the release film. On the back surface of the base material on which the pressure-sensitive adhesive layer A was formed, the obtained laminated film was superimposed in a state where the pressure-sensitive adhesive layer B was placed on the back surface of the base material to produce a laminated body. Then, by pressing the above-mentioned laminate with a rubber roll or the like, a double-sided pressure-sensitive adhesive tape having an adhesive layer on both surfaces of the base material and the surface of the adhesive layer being covered with a release film can be obtained.

In addition, two sets of laminated films were produced in the same manner, and for these laminated films, the pressure-sensitive adhesive layers of the laminated films were superimposed on each of both sides of the base material in a state of being opposed to the base material to produce a laminated body By pressing the laminated body with a rubber roll or the like, a double-sided pressure-sensitive adhesive tape having an adhesive layer on both surfaces of the base material and the surface of the adhesive layer being covered with a release film can be obtained.

The application of the pressure-sensitive adhesive tape according to one embodiment of the present invention is not particularly limited, but it is particularly suitable for fixing electronic equipment components and fixing vehicle-mounted components because of its excellent adhesive strength and heat resistance. Specifically, the adhesive tape which is an embodiment of the present invention can be suitably used for adhesion and fixation of electronic device components in large-sized portable electronic devices, adhesion and fixation of vehicle-mounted components (eg, vehicle-mounted panels), and the like.

In another embodiment of the present invention, there is also provided a method of fixing an electronic device part or an in-vehicle part using the above-mentioned adhesive tape. According to this method, not only can electronic equipment parts or vehicle-mounted parts be firmly fixed, but also the fixing can be continued even when exposed to high temperature.

Invention effect

According to the present invention, it is possible to provide an adhesive capable of exhibiting excellent adhesive force while increasing the content of bio-derived carbon, an adhesive tape using the adhesive, and a method for fixing electronic equipment parts or vehicle-mounted parts .

Detailed ways

Hereinafter, the embodiment of the present invention will be described in more detail by way of Examples, but the present invention is not limited to these Examples.

<Single A>

(1) Preparation of lauryl acrylate containing bioderived carbon

Lauryl acrylate is prepared by the esterification of acrylic acid with lauryl alcohol. Lauryl alcohol is prepared by hydrolyzing fats and oils contained in palm kernel oil, coconut oil, and the like, fractionating the obtained fatty acid, and hydrogenating the lauric acid extracted therefrom.

(2) Preparation of lauryl methacrylate containing carbon of biological origin

Lauryl methacrylate is prepared by esterifying methacrylic acid with lauryl alcohol obtained by the above method.

(3) Preparation of n-decyl methacrylate containing biologically derived carbon

N-decyl methacrylate is prepared by esterification of methacrylic acid with n-decanol. N-decyl alcohol is prepared by hydrolyzing fats and oils contained in palm kernel oil, coconut oil, and the like, fractionating the obtained fatty acid, and hydrogenating the capric acid thus taken out.

(4) Preparation of n-octyl acrylate containing biologically derived carbon

n-Octyl acrylate is prepared by the esterification of acrylic acid with n-octanol. The n-octanol is prepared by hydrolyzing fats and oils contained in palm kernel oil, coconut oil, etc., fractionating the obtained fatty acid, and hydrogenating the caprylic acid thus taken out.

(5) Preparation of isobornyl acrylate containing bioderived carbon

Isobornyl acrylate is prepared by reacting acrylic acid with camphene. The reaction method of acrylic acid and camphene is carried out by the method described in Japanese Patent Laid-Open No. 2006-69944. Camphene is obtained by isomerizing α-pinene obtained from pine resin and pine essential oil.

<Single B>

(1) Preparation of vinyl laurate containing carbon of biological origin

Vinyl laurate is prepared by hydrolyzing fats and oils contained in palm kernel oil, coconut oil, and the like, fractionating the obtained fatty acid, and vinylating the lauric acid extracted therefrom.

(2) Preparation of vinyl decanoate containing bioderived carbon

Vinyl caprate is prepared by hydrolyzing fats and oils contained in palm kernel oil, coconut oil, and the like, subjecting the obtained fatty acid to fractional distillation, and vinylating the capric acid thus extracted.

<Monomer containing bioderived carbon other than monomer A and monomer B>

Stearyl acrylate is prepared by the esterification of acrylic acid with stearyl alcohol. Stearyl alcohol is prepared by hydrolyzing fats and oils contained in palm oil, palm kernel oil, soybean oil, rapeseed oil, and the like, fractionating the obtained fatty acid, and hydrogenating the stearic acid extracted therefrom.

<Monomers of non-biological origin>

The following commercially available monomers were prepared as abiotic-derived monomers.

(1) 2-ethylhexyl acrylate (manufactured by Mitsubishi Chemical Corporation, glass transition temperature -70°C)

(2) Butyl acrylate (manufactured by Mitsubishi Chemical Corporation, glass transition temperature -55°C)

(3) Ethyl acrylate (manufactured by Mitsubishi Chemical Corporation, glass transition temperature -20°C)

(4) Methyl acrylate (manufactured by Mitsubishi Chemical Corporation, glass transition temperature -8°C)

(5) Acrylic acid (manufactured by Nippon Shokubai Corporation, glass transition temperature 106°C)

(6) Hydroxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., glass transition temperature -15°C)

<Crosslinking agent>

As the crosslinking agent, a commercially available polyisocyanate-based crosslinking agent (manufactured by Tosoh Corporation, CORONATE L-45) was prepared.

<Tackifier>

As the thickener, the following commercially available thickeners containing bio-derived carbon were prepared.

(1) Terpene phenol resin A (manufactured by YASUHARA CHEMICAL CO., LTD., G150, softening point: 150° C., bio-derived carbon content: 67% by weight)

(2) Polymerized rosin ester resin B (hydroxyl value: 46, softening point: 152°C, bio-derived carbon content: 95% by weight)

(3) Hydrogenated rosin ester resin C (manufactured by Arakawa Chemical Industry Co., Ltd., KE359, hydroxyl value: 40, softening point: 100° C., bio-derived carbon content: 95% by weight)

(Example 1)

(1) Production of (meth)acrylic copolymer

Ethyl acetate as a polymerization solvent was placed in the reaction vessel, and nitrogen was bubbled. Then, the reaction vessel was heated while nitrogen was flowing, and reflux was started. Next, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator 10 times with ethyl acetate was put into the reaction vessel, and 34 parts by weight of lauryl acrylate was added dropwise over 2 hours. , 48 parts by weight of n-octyl acrylate, 14 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid and 0.5 parts by weight of hydroxyethyl acrylate. After the dropwise addition, the polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator 10 times with ethyl acetate was put into the reaction vessel again, and the polymerization reaction was carried out for 4 hours. Thus, a solution containing the (meth)acrylic copolymer was obtained.

The glass transition temperature of the obtained (meth)acrylic copolymer was measured using a differential scanning calorimeter (DSC6220, manufactured by Seiko Instruments Inc.). The glass transition temperature was -44°C.

The dilution liquid obtained by diluting the obtained (meth)acrylic copolymer by 50 times with tetrahydrofuran (THF) was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm) to prepare a measurement sample . The measurement sample was subjected to gel permeation chromatography (2690 Separations Model, manufactured by Waters Corporation), and GPC measurement was performed under the conditions of a sample flow rate of 1 ml/min and a column temperature of 40° C. to measure the polymerization of the (meth)acrylic copolymer. The weight average molecular weight was calculated|required by styrene conversion molecular weight. The weight average molecular weight was 720,000.

(2) Manufacture of adhesive tape

To the obtained solution containing the (meth)acrylic copolymer, with respect to 100 parts by weight of the (meth)acrylic copolymer, 3 parts by weight of a crosslinking agent, 10 parts by weight of terpene phenol resin A, and a polymerized rosin ester resin were added 14 parts by weight of B and 10 parts by weight of hydrogenated rosin ester resin C to prepare a binder solution. The adhesive solution was applied on a release-treated PET film having a thickness of 75 μm so that the thickness of the adhesive layer after drying was 50 μm, and then dried at 110° C. for 5 minutes. The pressure-sensitive adhesive layer was superimposed on a release-treated PET film having a thickness of 75 μm, and was cured at 40° C. for 48 hours to obtain a pressure-sensitive adhesive tape (unsupported type).

The release film of one side of the obtained pressure-sensitive adhesive tape was peeled off, it was stuck on a PET film with a thickness of 50 μm, and it was cut into a flat rectangle of 20 mm×40 mm. Furthermore, the release film on the other surface of the pressure-sensitive adhesive tape was peeled off, a test piece was produced, and the weight was measured. After the test piece was immersed in ethyl acetate at 23°C for 24 hours, the test piece was taken out from the ethyl acetate and dried at 110°C for 1 hour. The weight of the test piece after drying was measured, and the gel percentage was calculated using the following formula. The gel percentage was 38% by weight.

Gel percentage (wt %)=100×(W ₅ -W ₃ )/(W ₄ -W ₃ )

(W ₃ : the weight of the above-mentioned PET film, W ₄ : the weight of the test piece before immersion in ethyl acetate, W ₅ : the weight of the test piece after immersion in ethyl acetate and drying)

(Examples 2 to 28, Comparative Examples 1 to 5)

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that the monomer of the (meth)acrylic copolymer and the tackifier to be blended into the pressure-sensitive adhesive tape were described in Tables 1 to 4. .

In addition, in Example 21, the double-sided adhesive tape which formed the adhesive layer of thickness 25 micrometers on both surfaces of a base material was manufactured. As the base material, nylon 610 (manufactured by Toray Industries, Ltd., CM2001), which is a plant-derived polyamide resin, was used as a film having a thickness of 25 μm.

Moreover, in Example 22, the double-sided adhesive tape which formed the adhesive layer of thickness 50 micrometers on both surfaces of a foam base material was manufactured by the following method.

The adhesive solution was applied on a release-treated PET film having a thickness of 75 μm so that the thickness of the adhesive layer after drying was 50 μm, and then dried at 110° C. for 5 minutes to obtain an adhesive layer A. This pressure-sensitive adhesive layer A is superimposed on a PE foam base material with a thickness of 100 μm and a foaming ratio of 3 times, and is pressurized with a rubber roller or the like, thereby producing a pressure-sensitive adhesive layer formed on the surface of the release film. A laminate. Next, another release film other than the above-mentioned release film was prepared and applied so that the thickness of the pressure-sensitive adhesive layer after drying was 50 μm, and then dried at 110° C. for 5 minutes, whereby pressure-sensitive adhesive layer B was obtained. The pressure-sensitive adhesive layer B is attached to the surface of the foam of the above-mentioned laminated body that faces the pressure-sensitive adhesive layer A, and is similarly pressurized with a rubber roller or the like, and then applied at 40°C. By curing at °C for 48 hours, a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both surfaces of the foam substrate was obtained.

(Evaluation)

The pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were evaluated by the following methods.

The results are shown in Tables 1 to 4.

(1) Content ratio of biologically derived carbon

About the obtained adhesive tape, the content rate of bioderived carbon was measured based on ASTM D6866.

(2) Measurement of peeling force in the plane direction

The double-sided adhesive tape with a width of 10 mm×10 mm was sandwiched between two SUS plates, and after being press-bonded with a weight of 5 kg for 10 seconds, the adhesive tape was cured for 24 hours under the conditions of 23° C. and 50% humidity. Then, two SUS plates were placed on a jig so as to be horizontal, the lower SUS plate was fixed, and the upper SUS plate was stretched in the vertical direction at a tensile speed of 10 mm/min, and the adhesion was measured. The force (N) when the belt is peeled off. The peeling force (Pa) in the plane direction was obtained by the following calculation.

Peeling force in the plane direction (Pa) = force at the time of peeling of the adhesive tape (N) ÷ area of the adhesive tape (m ² )

In addition, in the adhesive tape of Example 22, the peeling force in the plane direction was very high, and the foam base material was destroyed in the step of exceeding 0.8 MPa.

(3) Determination of peel force in shear direction

The double-sided adhesive tape with a width of 10 mm×10 mm was sandwiched between two SUS plates, and after being press-bonded with a weight of 5 kg for 10 seconds, the adhesive tape was cured for 24 hours under the conditions of 23° C. and 50% humidity. Then, two SUS plates were placed on the jig in a vertical manner, one SUS plate was fixed to the lower workpiece fixture, and the other SUS plate was fixed to the upper workpiece fixture, and then the tensile speed was 10mm/min. The upper workpiece holder was pulled in the vertical direction under the same conditions, and the force (N) when the adhesive tape was peeled was measured. The shearing direction peeling force (Pa) was obtained by the following calculation.

Peeling force in the shearing direction (Pa) = force when the adhesive tape is peeled off (N) ÷ area of the adhesive tape (m ² )

In addition, in the adhesive tape of Example 22, the peeling force in the shearing direction was very high, and the foam base material was destroyed in the step of exceeding 0.8 MPa.

[Table 1]

[Table 2]

[table 3]

[Table 4]

Industrial Availability

According to the present invention, it is possible to provide an adhesive capable of exhibiting excellent adhesive force while increasing the content of bio-derived carbon, an adhesive tape using the adhesive, and a method for fixing electronic equipment parts or vehicle-mounted parts .

Claims (13)

1. An adhesive comprising a (meth) acrylic copolymer containing 48% by weight or more of a structural unit derived from a monomer A and/or a monomer B, wherein the monomer A contains biogenic carbon and is represented by the following general formula (1), the monomer B contains biogenic carbon and is represented by the following general formula (2), and the glass transition temperature of the (meth) acrylic copolymer is-20 ℃ or lower,

in the formula (1), R¹Represents H or CH₃，R²represents-C_nH_2n+1N represents an integer of 7 to 14,

in the formula (2), R³represents-C (═ O) C_mH_2m+1M represents an integer of 7 to 13,

R²and R ³The carbon in (b) is of biological origin.

2. The adhesive according to claim 1, wherein the monomer A is at least 1 selected from the group consisting of n-octyl (meth) acrylate, lauryl (meth) acrylate and decyl (meth) acrylate.

3. The adhesive according to claim 1, wherein the monomer A is lauryl acrylate and/or lauryl methacrylate.

4. The adhesive of claim 1, wherein the monomer B is vinyl decanoate and/or vinyl laurate.

5. The adhesive according to claim 1, 2, 3 or 4, wherein the (meth) acrylic copolymer contains the structural unit derived from the monomer A, and the structural unit derived from lauryl acrylate and/or lauryl methacrylate is 48% by weight or more of the structural unit derived from the monomer A.

6. The adhesive according to claim 1, 2, 3, 4, or 5, wherein the (meth) acrylic copolymer contains the structural unit derived from the monomer A, and in the structural unit derived from the monomer A, the structural unit derived from lauryl acrylate is 10 to 90% by weight, and the structural unit derived from lauryl methacrylate is 10 to 90% by weight.

7. The adhesive according to claim 1, 2, 3, 4, 5 or 6, wherein the (meth) acrylic copolymer has a structural unit derived from an alkyl (meth) acrylate having an alkyl group with a carbon number of 16 to 24.

8. The adhesive according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the rosin-based tackifier and/or the terpene-based tackifier of biological origin is contained in an amount of 10 to 50 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer.

9. An adhesive tape having an adhesive layer comprising the adhesive of claim 1, 2, 3, 4, 5, 6, 7, or 8.

10. The adhesive tape according to claim 9, further comprising a substrate, and the substrate is a film formed of polyester or polyamide.

11. The adhesive tape of claim 9, further having a foam substrate.

12. The adhesive tape according to claim 9, 10 or 11, which is used for fixing an electronic device part or an in-vehicle part.

13. A method of fixing an electronic device part or a vehicle-mounted part using the adhesive tape of claim 9, 10, or 11.